Derivatives And Other Financial Instruments (Fair Value Gains And Losses on Derivatives Contracts) (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	$ 4	$ (35)	$ 32	$ (53)
Sales [Member] | Aluminum Contracts [Member]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	(10)	7	(9)	3
Other Expenses (Income), Net [Member] | Aluminum Contracts [Member]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	18	(33)	7	(18)
Other Expenses (Income), Net [Member] | Embedded Credit Derivative [Member]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	(13)	1	(10)	(8)
Other Expenses (Income), Net [Member] | Energy Contract [Member]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	16	(12)	47	(31)
Other Expenses (Income), Net [Member] | Foreign Exchange Contracts [Member]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	$ (7)	$ 2	$ (3)	$ 1